A novel qualitative point-of-care test of activated matrix metalloproteinase-8 (aMMP-8) using noninvasive oral rinse sampling procedures has been developed for the early detection of collagen breakdown indicating periodontal tissue destruction. The main object of this study was to assess the reliability of the test in a low-income setting to identify participants with history of periodontal destruction detected as alveolar bone loss (ABL) in radiographs. This cross-sectional study included 486 women who had recently delivered in rural Malawi. The aMMP-8 test and dental panoramic radiographs were taken within 48 h of delivery. The performance of the test in comparison to radiological examinations was tested by following the standards for reporting of diagnostic accuracy studies protocol (STARD) with respective statistical measures and 95% confidence intervals. From the 486 eligible participants, 461 mothers with complete data, aged from 15 to 46 years (mean 24.8, SD 6.0) were included in the analysis. ABL was identified in 116 of 461 participants. There was 56% agreement between the aMMP-8 test results and detected ABL (yes or no) in radiographs. Calculated sensitivity of the test was 80% (72⁻87%), specificity 48% (43⁻54%), positive predictive value 34% (31⁻37%), negative predictive value 88% (83⁻91%), positive likelihood ratio 1.55 (1.35⁻1.77), and negative likelihood ratio 0.41(0.28⁻0.60). The aMMP-8 test sensitivity and negative predictive value to identify the ABL cases were relatively high, but there was additionally a high rate of test-positive results in participants without ABL, especially in young mothers, leading to low overall agreement between the test results and radiological bone loss. Further longitudinal studies are needed to examine if the test positive subjects are in risk of future bone loss before the detectable signs of periodontitis in radiographs.
Keywords: alveolar bone loss; matrix metalloproteinase (MMP)-8; periapical infection; periodontitis; point-of-care testing; saliva.